The Scarlets were left battered and bruised by Treviso at Parc y Scarlets as they went down to a surprise defeat to the Italian side.

Despite the heavy 41-17 loss, Simon Easterby's side still qualified for a semi-final away to Ulster though they will have to improve dramatically if they are to win at Ravenhill and reach the final.

It was a result no one inside Parc y Scarlets expected but it was entirely deserved as Treviso outscored the Scarlets by four tries to one.

Scores from Robert Barbieri, Manoa Vosawai, Luca Morisi and Christian Loamanu completed a superb performance with Kris Burton kicking the rest of the points in a controlled display.

The Scarlets had trailed by just a point at the break but a poor second period saw the Italians pull clear despite being down to 13 men at one stage.

An early Owen Williams penalty had given the Scarlets a 3-0 lead but when a line-out for the home side went awry, Treviso pounced. It was Barbieri who was the scorer, exposing the Scarlets at the heart of their defence to crash over following a superb break from lock Francesco Minto.

Burton, who is bound for the Dragons next season, converted and the Italian side led 7-3. The early try was an indication of Treviso's willingness to play but a couple of further Williams penalties, either side of one from Burton, meant the Scarlets trailed 10-9 after 20 minutes.

Traditionally physical up front, Treviso were showing that in perfect conditions at Parc y Scarlets, they were more than prepared to run the ball too. Italian international Alessandro Zanni was impressing in what was an open game, linking the forwards and backs impressively.

Save one superb break from his own line by centre Scott Williams, it was Treviso who were on top though the final pass seemed to let them down at the vital moment. As a result, they failed to extend their lead and when the Scarlets won a scrum penalty following a huge forward drive, Williams continued his 100 per cent record.

Easterby's Scarlets may have been on top at scrum time but after Burton struck his second penalty and Williams surprisingly pushed a simple kick wide, Treviso led by a point at the break.

If the Scarlets had been disappointed with their first half performance, Easterby's mood wouldn't have improved following Burton's third penalty seconds after half time.

At 16-12 up, Treviso were ensuring it was a nervy evening at Parc y Scarlets as they continued to do more than hold their own. But when the Scarlets upped the pressure on the Italian line, Treviso were dealt a hammer blow in double quick time. Valerio Bernabo and Jacobus Roux were both yellow carded and down to 13 men on their own line, it seemed only a matter of time before the Scarlets would regain the lead.

But not only did Treviso escape, they promptly went down the other end and extended their lead. Burton kicked his fourth penalty before remarkably, Vosawai scored Treviso's second try, crossing in the corner despite the attentions of Ken Owens.

Burton converted and despite being two men light, Treviso led a shell shocked Scarlets 26-12.

Everything seemed to be going wrong for the Scarlets, a knock on from George North summing up what had been a shocking second half. And despite the introductions of Rhys Priestland, Matthew Rees and Gareth Davies, there was little in the way of a reply from the men in red.

And when Morisi waltzed clear for Treviso's third try, the game was up for the Scarlets. There was still time for Loamanu to score a fourth and for Burton to convert and add a 50 metre penalty in a convincing win.

Liam Williams scored a consolation on the final whistle but it was Treviso who took all the plaudits.

Luckily for the Scarlets, the Ospreys' defeat to Leinster meant they have a chance to atone for this performance in next Friday's semi-final.